It's not too difficult, but you will need a lot of PB Blaster and a good jack stand. Block the front wheels of course.

In the rear, you will have to take out a few floor panels to access the top of the shock mount and remove the bolts. Then jack the spring pan to take the load off the shock and remove it from the bottom.

Lower the jack slowly and remove it from under the car. Unbolt, more penetrating oil, the spring lower mounting from the trailing arm and remove the spring.

During reassembly, I found it easier to put the top of the shock in the car first, but that was a long time ago and memory is fading.
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My back feels better when I sit in a Volvo seat